Towards the elimination of Chromium VI in coil coating

In the last years research in the coil coating industry has been focused in the formulation of chrome free passivating agents.

CONDOROIL's research department is well active in this field, in particular for the development of an innovative product that uses a new class of molecules. In collaboration with CNR-ISMAC of Biella (Institute for macromolecular studies of the Italian National Research Center) CONDOROIL is conducting a study about macromolecules that provide anti-corrosive properties to metal surfaces. Among them, particular attention is given to polypirrole (ppy), a conductive polymer with anticorrosive properties. Recent studies have shown anticorrosive properties of electro-deposited films of ppy on metals. This kind of application does not comply with the application techniques used in the coil coating industry. CONDOROIL and CNR have developed stable dispersions of ppy that permit its application in the common industrial coaters. Despite the good results in the stabilization of the ppy dispersions, the results as corrosion protection were not as positive. Indeed HDG panels treated with ppy, alone or mixed in an inorganic formulation, showed 100% of corrosion after 24 h of exposure to the neutral salty spray test. The results of the tests show that ppy properties depend on the synthesis method. Electrodeposited ppy films have a better adherence on the metal surface, giving better corrosion resistance. The research continued with the formulation of ppy into products for paint pretreatment, in order to improve paint adhesion. The results showned that ppy is inadequate for this application. A scientific paper on this study is about to be published.

CONDOROIL and CNR are now working on the study of other alternative polymers for metal protection.